<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <!-- 下拉菜单 -->
  <!-- select：表示下拉菜单的整体 -->
  <!-- option：表示下拉菜单的每一项 -->
  所在城市：<select>
            <option>上海</option>
            <option selected>北京</option>
            <option>广州</option>
            <option>深圳</option>
          </select>
</body>
</html>